Spinning and twisting machines are already known which make a twisted product from two strands of roving wound together on a spindle and run together shortly after issuing from a supply roll pair, e.g. the last pair of rolls of a drafting frame.
To avoid single strand or flawed yarn, after breakage of one roving strand, devices (yarn-breakers) are provided which also break the remaining roving strand so that both strands can be retied after spindle standstill.
One such yarn-breaker comprises a pivotable yarn breaking device with two parallel elements close to each other between which the already united roving strands run (see German Patent Document Open Patent application DE-OS No. 31 33 372).
On breakage of one of the roving strands, this yarn breaking device is tilted from a normal stable position, i.e. the operating position, by the remaining roving strand and automatically moves into a position in which both arms prevent the production of the twist in the remaining roving strand so that this strand is soon broken. This latter position is the yarn breaking position. Before refeeding the yarn to the spindle, thereby repairing the break, the yarn breaking device in these spinning machines must again be located in its normal position and the yarn fed between both parallel elements.